Based on the advise of our Enterprise Geodatabase administrator, I looked at using branch versioning my data on our Enterprise Geodatabase to be able to keep the original data 'clean' (the DEFAULT version) and allowing a client to make changes in a predefined version. This way, I'm able to reconcile the changes before posting them to the default version. Testing this behavior shows that this works fine when using the data in ArcGIS Pro. But we use these services in eg. web maps, web map applications and storymaps either through a PDS, ArcGIS Online or an Enterprise environment. Every change I make through these portals immediately appears in the default version and I can't figure out how to change this.